The world’s reefs are under increasing threat from manmade depredations.They are too valuable a resource to be lost

In a few weeks, members of Unesco’s world heritage committee will
meet in Bonn to discuss a simple, but disturbing proposition: that
Australia’s Great Barrier Reef,
the world’s largest coral reef system, be listed as being “in danger”.
The reef, worth an estimated $Aus5bn (£2.6bn) a year in tourism to the
nation, is a world heritage site and contains more than 400 types of
coral and 1,500 species of fish.
Set in turquoise waters off the coast
of Queensland, the 1,400-mile reef is one of the planet’s greatest
wonders, but is now being eroded at an alarming rate.

Rising sea temperatures, increasing ocean acidification, swelling
numbers of cyclones in recent years, pollution problems triggered by
fertiliser and sewage run-offs from farms and cities, and damage caused
by the development of ports on the east coast of Australia to help the
country to supply China with coal have had a combined and devastating
effect on the Great Barrier Reef.

In the past 30 years, it has lost half its coral.
Had the Taj Mahal,
another world heritage site, lost half its structure, there would be no
doubt that it would be deemed to be in danger.
Hence the pressure from
green groups to give the reef such a listing, a damning status that has
so far been awarded to only 46 of Unesco’s total of 1,007 world heritage sites.

The prospect has only recently produced a response from the Australian government.
Its prime minister, Tony Abbott,
has realised that the tainting of one of his country’s major
attractions as being in danger – and, by inference, poorly managed – is
not good for tourism and has hastily introduced measures to curtail
pollution and given pledges to spend several billion dollars on reef
relief work.
It remains to be seen if these measures will be enough to halt the
Great Barrier Reef’s decay or save it from an “in danger” listing by
Unesco.
There is, in fact, only a limited amount that Australia can do
on its own to save the reef.
Many factors lie beyond the nation’s
immediate control.
In particular, rising temperatures round the world
and increased ocean acidification, both caused by soaring global
emissions of carbon dioxide, are today destroying coral across the
planet, while a third factor, over-fishing, has now brought the status
of most reefs to crisis level.

This is what the Great Barrier Reef looks like from where ISS space station

(Photo: NASA, Astronaut Wheelock)

According to a report co-authored by British and Australian scientists
and published last week, the planet’s already beleaguered coral reefs,
which are some of Earth’s most important nurseries for marine life, are
now being further assailed by industrial fishing fleets.
The researchers
examined more than 800 reefs in 64 locations around the world and found
that 83% had lost more than half of their fish, most of these losses
having occurred since the 1970s.
Apart from the danger posed to many
species of fish, the impact on reefs themselves is also alarming, the
scientists warn.
Rudderfish, parrotfish, damselfish and other reef
denizens eat invertebrates and remove algae, which can smother and kill
off coral.
Take away these piscine predators and the reef starts to
decay.
And even when protective measures to control and limit fishing
are imposed, it can take up to 60 years for a reef to recover.

BBC report

It is a gloomy vision, though the authors of the report also point
out that they were encouraged to find that, when some form of management
is imposed at a reef, substantial amounts of biomass, both fish and
coral, can survive there.
In other words, by managing fisheries, some
coral reefs could be given a chance to thrive.

In the long term, however, it is hard to be optimistic.
Rising ocean
acidification – “the evil twin of global warming” – will continue until
fossil fuel burning and carbon dioxide emissions are curtailed by
international agreement.
Only then is there a chance that coral reef
erosion will stop.
We should be under no illusions about what is at risk. Coral reefs
occupy less than 0.1% of the world’s ocean surface, but provide homes
for around a quarter of all marine species.
Their value to the planet
was once summed by David Attenborough in an interview in the Observer.
As he observed, if you want beauty and if you want to see wildlife,
there is no better prospect than a visit to a coral reef.
These places
abound with brilliantly coloured fish and corals.
As Attenborough put
it, the sight is mind-blowing.
The world therefore has a choice: curtail
industrial fishing and limit carbon emissions – or risk losing these
natural wonders forever.